Hydrogen can be considered to be a promising energy alternative to carbon-based fuels. Various technologies have been developed regarding the production and use of hydrogen as a fuel or energy source. While hydrogen may be considered to be a clean and desirable energy alternative to carbon-based fuels, various obstacles may exist in relying on hydrogen as an energy source as opposed to other forms of energy. Such obstacles may generally include the ability to efficiently, safely and economically produce, transport and store hydrogen.
One approach to producing hydrogen can include thermochemical processes. One such process can include carrying out chemical reactions between a sulfur-iodine compound and water at high temperatures (e.g., above approximately 800 degrees C.). Generally, the process can result in the splitting of the water molecules (H2O) into hydrogen (H2) and oxygen (O2). The sulfur-iodine solution can be recycled in the process and therefore, other than hydrogen and oxygen, there may be no harmful byproducts.
Another approach to producing hydrogen can include the electrolysis of water. Electrolysis requires the use of electricity, in accordance with Faraday's Law. Electrolysis can be a relatively inefficient process for producing hydrogen without the aid of another energy source (beyond the supply of electricity). Indeed, the energy consumed may be more valuable than the hydrogen produced. In order to make electrolysis an economically viable process, another energy source can be incorporated into the process. For example, high-temperature electrolysis utilizes a high-temperature heat source to heat the water and effectively reduce the amount of electrical energy required to split the water molecules into hydrogen and oxygen with higher efficiencies. Another approach can involve the extraction of hydrogen from fossil fuels, such as natural gas or methanol. This method can be complex and result in residues, such as carbon dioxide. Also, there is a worldwide limit to the amount of fossil fuel available for use in the future.
Other approaches are needed to address hydrogen production, such that the hydrogen production may be carried out in an effective, efficient and safe manner. A hydrogen-based economy can be a long-term, environmentally-benign energy alternative for sustainable growth. An increasing demand for hydrogen may arise as the worldwide need for more electricity increases, greenhouse gas emission controls tighten, and fossil fuel reserves wane.